Sterol O-acylcoenzyme A: cholesterol acyltransferase 1 (SOAT1): a new predictive marker for aggressiveness of adrenocortical carcinomas

Introdução: O carcinoma do córtex suprarrenal (CCS) é uma malignidade rara associada a um prognóstico reservado na maioria dos pacientes. Além do prognóstico desfavorável, as alternativas de tratamento são escassas e, apesar de muitos progressos no conhecimento da patogênese da doença, pouco se evoluiu em relação a sua terapêutica. Desta forma, o estabelecimento de novos marcadores prognósticos que possam contribuir para o desenvolvimento de tratamentos-alvo é de grande interesse. A esterol O-acilcoenzima A: colesterol aciltransferase 1 (SOAT1) é uma enzima codificada pelo gene SOAT1, o qual é alvo da ação do fator de transcrição esteroidogênico 1 (SF-1). A SOAT1 está envolvida na esterificação do colesterol e na formação das partículas de gordura ou \"lipid droplets\". Recentemente foi demonstrado que a inibição in vitro da SOAT1 resulta em comprometimento da esteroidogênese e da viabilidade celular no CCS. Até o momento não há estudos que avaliaram o impacto da expressão da SOAT1 no prognóstico e nos desfechos clínicos de pacientes com CCS. Objetivos: Avaliar a expressão do gene e da proteína SOAT1 no CCS e correlacioná-la com as características clínicas, bioquímicas e anatomopatológicas e com os desfechos clínicos sobrevida livre de recorrência (SLR), sobrevida livre de progressão (SLP) e sobrevida global (SG); avaliar a expressão proteica da SOAT1 no tumor primário versus a expressão proteica deste marcador em metástases de CCS em diferentes sítios; comparar a expressão proteica da SOAT1 com a expressão do SF-1 e avaliar o impacto da expressão proteica da SOAT1 na resposta ao tratamento com mitotano. Métodos: Analisamos a expressão gênica e proteica da SOAT1 avaliada por meio da reação em cadeia da polimerase quantitativa em tempo real (qRT-PCR) e por imuno-histoquímica (IHQ) em três micromatrizes teciduais (TMAs): dois TMAs foram confeccionados a partir de amostras tumorais de carcinomas primários (escore de Weiss ? 3) de 112 pacientes adultos e um TMA foi confeccionado a partir de amostras tumorais de 42 metástases de CCS de 19 pacientes. Dois patologistas experientes avaliaram os resultados imuno-histoquímicos de forma cega e independente utilizando uma abordagem semi-quantitativa. Resultados: A expressão proteica da SOAT1 foi heterogênea. Na série de tumores primários e de metástases, 37,5% e 36%, respectivamente, apresentaram expressão proteica forte (escore > 2). A expressão forte da proteína SOAT1, nos tumores primários, correlacionou-se com características de maior agressividade no CCS como com a secreção excessiva de cortisol pelo tumor e com o status de hipercortisolismo (p = 0,01), com o estadiamento avançado ao diagnóstico (ENSAT 3 e 4; p = 0,011) e com um índice de proliferação celular Ki67 mais elevado (p = 0,002). A expressão forte da SOAT1 foi um fator preditivo independente para uma menor SG (risco relativo (RR) 2,15; intervalo de confiança (IC) 95% 1,26-3,66; p = 0,005) e para uma menor SLR em pacientes com doença localizada ao diagnóstico que foram submetidos à ressecção cirúrgica completa do tumor primário (RR 2,1; IC 95% 1,09-4,06; p = 0,027). Nas metástases a expressão proteica da SOAT1 enquadrou-se na mesma categoria de expressão que a do tumor primário em 72% dos casos; contudo, não se correlacionou de forma estatisticamente significante com as características clínicas, bioquímicas e histológicas. A expressão do SF-1 foi positiva na maioria dos casos, tendo sido demonstrada em 92% dos tumores primários e em 74% das metástases. A expressão da SOAT1 e do SF-1 foram concordantes em cerca de dois terços dos casos. A expressão proteica da SOAT1, isoladamente, não predisse a resposta ao tratamento com mitotano, tanto no contexto adjuvante quanto no contexto paliativo. Conclusões: A expressão proteica da SOAT1 tem valor prognóstico no CCS, definindo um subgrupo de pacientes com prognóstico mais reservado. Reforçamos a importância de que a SOAT1 seja investigada como um possível alvo terapêutico nos pacientes portadores desta neoplasia malignaIntroduction: Adrenocortical carcinoma (ACC) is a rare cancer associated with poor prognosis in most patients. In addition to the unfavorable prognosis, alternative treatments are lacking, and there has been a lack of significant advances in the development of treatments. Thus, the establishment of new prognostic markers that can contribute to the development of target therapies is of enormous interest. Sterol O-acylcoenzyme A: cholesterol acyltransferase 1 (SOAT1) is an enzyme encoded by the SOAT1 gene, which is the target of steroidogenic transcription factor 1 (SF-1). SOAT1 is an enzyme involved in cholesterol esterification and lipid droplet formation. Recently, it was demonstrated that, in vitro, SOAT1 inhibition leads to impaired steroidogenesis and cell viability in ACC. To date, no studies have addressed the impact of SOAT1 expression on ACC prognosis and clinical outcomes. Aims: We aimed to evaluate the correlation between SOAT1 expression and the clinical, biochemical and anatomopathological characteristics, recurrence-free survival (RFS), progression-free survival (PFS) and overall survival (OS) associated with ACC and to evaluate SOAT1 protein expression in the primary tumor versus that in ACC metastases at different sites. We also intended to compare SOAT1 protein expression with SF-1 expression and to evaluate the impact of SOAT1 protein expression in response to treatment with mitotane. Methods: We evaluated SOAT1 gene and protein expression through real-time quantitative polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) in three tissue microarrays (TMAs), respectively. Two TMAs were prepared from primary carcinoma samples (Weiss score ? 3) from 112 adult patients, and one TMA was prepared from tumor samples from 42 ACC metastases from 19 patients. Two experienced pathologists evaluated the immunohistochemical results blindly and independently using a semiquantitative approach. Results: SOAT1 protein expression was heterogeneous. Among the primary tumors and metastases, 37.5% and 36%, respectively, demonstrated strong protein expression (score > 2). In the primary tumors, strong SOAT1 protein expression was correlated with features of high aggressiveness in ACC, such as excessive cortisol secretion by the tumor and with the hypercortisolism status (p = 0.01), with an advanced stage at diagnosis (ENSAT 3 and 4; p = 0.011) and with a higher Ki67 index (p = 0.002). Strong SOAT1 protein expression was an independent predictive factor of decreased OS (hazard ratio (HR) 2.15; 95% confidence interval (CI) 1.26-3.66; p = 0.005) and decreased RFS in the subgroup of patients with localized disease at diagnosis who underwent complete surgical resection of the primary tumor (HR 2.1; 95% CI 1.09-4.06; p = 0.027). For the metastases, the level of SOAT1 protein expression resulted in their being included in the same expression category as the primary tumor in 72% of the cases, but it was not correlated in a statistically significant way with the clinical, biochemical or histological characteristics. The SF-1 expression status was positive in most cases (92% of primary tumors and 74% of metastases). The expression levels of SOAT1 and SF-1 were similar in approximately two-thirds of the cases. SOAT1 expression alone did not predict the response to treatment with mitotane in both the adjuvant and palliative settings. Conclusions: Our findings demonstrated that the detection of SOAT1 protein expression has prognostic value in ACC, defining a subgroup of patients with poorer prognosis. We also reinforced the importance of investigating SOAT1 as a possible therapeutic target for patients with AC

Low Protein Expression of both ATRX and ZNRF3 as Novel Negative Prognostic Markers of Adult Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare malignancy that is associated with a dismal prognosis. Pan-genomic studies have demonstrated the involvement of ATRX and ZNRF3 genes in adrenocortical tumorigenesis. Our aims were to evaluate the protein expression of ATRX and ZNRF3 in a cohort of 82 adults with ACC and to establish their prognostic value. Two pathologists analyzed immuno-stained slides of a tissue microarray. The low protein expression of ATRX and ZNRF3 was associated with a decrease in overall survival (OS) (p = 0.045, p = 0.012, respectively). The Cox regression for ATRX protein expression of >1.5 showed a hazard ratio (HR) for OS of 0.521 (95% CI 0.273–0.997; p = 0.049) when compared with ≤1.5; for ZNRF3 expression >2, the HR for OS was 0.441 (95% CI, 0.229–0.852; p = 0.015) when compared with ≤2. High ATRX and ZNRF3 protein expressions were associated with optimistic recurrence-free survival (RFS) (p = 0.027 and p = 0.005, respectively). The Cox regression of RFS showed an HR of 0.332 (95%CI, 0.111–0.932) for ATRX expression >2.7 (p = 0.037), and an HR of 0.333 (95%CI, 0.140–0.790) for ZNRF3 expression >2 (p = 0.013). In conclusion, low protein expression of ATRX and ZNRF3 are negative prognostic markers of ACC; however, different cohorts should be evaluated to validate these findings

Sterol O-acyl transferase 1 as a prognostic marker of adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with an unfavorable prognosis. Despite the poor prognosis in the majority of patients, no improvements in treatment strategies have been achieved. Therefore, the discovery of new prognostic biomarkers is of enormous interest. Sterol-O-acyl transferase 1 (SOAT1) is involved in cholesterol esterification and lipid droplet formation. Recently, it was demonstrated that SOAT1 inhibition leads to impaired steroidogenesis and cell viability in ACC. To date, no studies have addressed the impact of SOAT1 expression on ACC prognosis and clinical outcomes. We evaluated SOAT1 expression by quantitative real-time polymerase chain reaction and immunohistochemistry in a tissue microarray of 112 ACCs (Weiss score ≥ 3) from adults treated in a single tertiary center in Brazil. Two independent pathologists evaluated the immunohistochemistry results through a semiquantitative approach (0–4). We aimed to evaluate the correlation between SOAT1 expression and clinical, biochemical and anatomopathological parameters, recurrence-free survival (RFS), progression-free survival (PFS), and overall survival (OS). SOAT1 protein expression was heterogeneous in this cohort, 37.5% of the ACCs demonstrated a strong SOAT1 protein expression (score > 2), while 62.5% demonstrated a weak or absent protein expression (score ≤ 2). Strong SOAT1 protein expression correlated with features of high aggressiveness in ACC, such as excessive tumor cortisol secretion (p = 0.01), an advanced disease stage [European Network for the Study of Adrenal Tumors (ENSAT) staging system 3 and 4 (p = 0.011)] and a high Ki67 index (p = 0.002). In multivariate analysis, strong SOAT1 protein expression was an independent predictor of a reduced OS (hazard ratio (HR) 2.15, confidence interval (CI) 95% 1.26–3.66; p = 0.005) in all patients (n = 112), and a reduced RFS (HR 2.1, CI 95% 1.09–4.06; p = 0.027) in patients with localized disease at diagnosis (n = 83). Our findings demonstrated that SOAT1 protein expression has prognostic value in ACC and reinforced the importance of investigating SOAT1 as a possible therapeutic target for patients with ACC